@Override
 public MasterKey getContainerTokenMasterKey() {
   NodeHeartbeatResponseProtoOrBuilder p = viaProto ? proto : builder;
   if (this.containerTokenMasterKey != null) {
     return this.containerTokenMasterKey;
   }
   if (!p.hasContainerTokenMasterKey()) {
     return null;
   }
   this.containerTokenMasterKey = convertFromProtoFormat(p.getContainerTokenMasterKey());
   return this.containerTokenMasterKey;
 }